A. Paepcke. Object-Oriented Programming, глава User-level language crafting: introducing the CLOS metaobject protocol, MIT Press, Cambridge, MA, USA, (1993)
R. Brooks, R. Gabriel, и G. Steele Jr.. International Joint Conference on Artificial Intelligence, 2, стр. 845--849. Karlsruhe, West Germany, William Kaufman, (августа 1983)
R. Brooks, R. Gabriel, и J. Steele. LFP '82: Proceedings of the 1982 ACM symposium on LISP and functional programming, стр. 108--113. New York, NY, USA, ACM, (1982)